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'97 CL600
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Discussion Starter #1
The check engine light came on. It is a '97 Cl600 with about 70K. I've gotten not to trust any code indications since everyone seems to be different for the same problem. My old shop has closed their doors and I am with a new (old) shop now. They got a reading of P0173-134 I don't understand the "134" after the 173. I have the code list and it is not on there. Or is it saying there are TWO codes, 173 and 134? Any ideas? And the car runs like the dream it has always been!
Anziani
 

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1996 S500
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The check engine light came on. It is a '97 Cl600 with about 70K. I've gotten not to trust any code indications since everyone seems to be different for the same problem. My old shop has closed their doors and I am with a new (old) shop now. They got a reading of P0173-134 I don't understand the "134" after the 173. I have the code list and it is not on there. Or is it saying there are TWO codes, 173 and 134? Any ideas? And the car runs like the dream it has always been!
Anziani
It sounds like two codes that would be related P0134 is for O2 Sensor and P0173 is fuel trim related. Maybe you just have a bad O2 sensor causing both.


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'97 CL600
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2,845 Posts
Discussion Starter #3
Thanks w140w124, That was my thinking also. I couldn't see what version of Star C he was using but he did mention that he is interested in buying a newer model than Mdl C. Maybe his older model runs the codes sequentially.
Anziani
 

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94 - S500 Cpe
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354 Posts
They got a reading of P0173-134 I don't understand the "134" after the 173. I have the code list and it is not on there. Or is it saying there are TWO codes, 173 and 134?
Anziani
If there are TWO (2) codes, then:
  • P0134 O2 Sensor Circuit - No Activity Detected (Bank 1 Sensor 1)
  • P0174 System - Too Lean (Bank 2)
Could be #1 O2 sensor bit the dust?? Or bad/ohmic connection??
 

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Premium Member
1999 S600 & 1999 S500
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803 Posts
Anziani,
You may have already searched but this may help. Interesting that the PO134 is Bank 1 which is right side (passenger) and the PO173 is Bank 2 which is Left side (driver side).
There are a number of OBD-II trouble codes that refer to either Bank 1 or Bank 2. ... Quite simply, Bank 1 refers to the side of the engine that has the #1 cylinder. Bank 2 is the opposite side of the engine. It's not correct to simply state that driver's side is always cylinder #1 or vice versa. (I just learned what determines Bank 1 vs Bank 2. I knew bank 1 was passenger side for the M120 but did not know why).

I just read my codes I have been getting the PO170 which is left bank. I also got PO301to 306. I changed all plugs and boots and most of the coils. It was time anyway. Did not help. I am now also getting PO410 which is another indicator of O2 sensor. I have a PO156 pending, which is Bank @ second O2 sensor. Looks like I may need to get professional help and also carry the car to a shop.

Hope th einfo below helps.

Image result for m120 cylinder numbering

P0134 MERCEDES-BENZ Possible Causes
  • Faulty Front Heated Oxygen Sensor Bank 1
  • Front Heated Oxygen Sensor Bank 1 harness is open or shorted
  • Front Heated Oxygen Sensor Bank 1 circuit poor electrical connection
  • Inappropriate fuel pressure
  • Faulty fuel injectors
  • Intake air leaks may be faulty
  • Exhaust gas leaks
P0173 MERCEDES-BENZ - Fuel Trim Malfunction Bank 2
Possible causes
  • Intake air leaks
  • Faulty front heated oxygen sensor
  • Ignition misfiring
  • Faulty fuel injectors
  • Exhaust gas leaks
  • Incorrect fuel pressure
  • Lack of fuel
  • Faulty Mass Air Flow (MAF) sensor
  • Incorrect Positive Crankcase Ventilation (PCV) hose connection
 

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'97 CL600
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2,845 Posts
Discussion Starter #6
Thank you quaker city. Yes, that helps a lot, especially the Bank layout. I'm leaning towards a O2 sensor at the moment. The engine only has 69K on it.
Anziani
 

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1999 S600 & 1999 S500
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803 Posts
You can buy a code reader , mine is by Genscan for $20 to $30. You can also erase the codes after you scan. They also come with a list of the codes.

Good Luck!
 

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94 - S500 Cpe
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If there are TWO (2) codes, then:
  • P0134 O2 Sensor Circuit - No Activity Detected (Bank 1 Sensor 1)
  • P0174 System - Too Lean (Bank 2)
Could be #1 O2 sensor bit the dust?? Or bad/ohmic connection??
You missed my post??
I think it's a heater/failed O2 element for Bank1 O2. . . . :unsure:
 

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1994 s600 coupe
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364 Posts
you need to put it on a scan tool with LIVE DATA, and read the sensor values for coolant temp, o2 voltage and see if it's going into closed loop.
also check the function of throttle position sensor, MAP sensor, intake air sensor, MAF sensor, throttle angle, idle position
when I got my car it had one o2 with broken off tip inside exhaust, and the other one barely transmitting. the voltages were way down low under 200mv,
one was only 50mv. you can get new o2 sensors for only $26 on Ebay now, with the proper 4 pin circular locking plug
 

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'97 CL600
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2,845 Posts
Discussion Starter #10
You missed my post??
I think it's a heater/failed O2 element for Bank1 O2. . . . :unsure:
Jim,
Sorry I didn't respond. Yes, I checked my records and both downstream sensors were replaced but not the upstream sensors. I'm searching sensors now but will only use Bosch or something equal. No eBay or Chinese stuff on my car!
Anziani
 

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1994 s600 coupe
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364 Posts
I can vouch for these offshore o2 sensors, yes they're from China, but they work. I put 2 in my car.

 

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'97 CL600
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2,845 Posts
Discussion Starter #12
Sorry 1994. It is a matter of principle with me. No Chinese products. They are the enemy of the USA, not Russia. They have stolen intellectual property and done everything they can to undermine us.
Anziani
 

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1994 s600 coupe
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364 Posts
Anziani I understand totally. in my case, for a car I may not keep indefinitely anyway, that is one of the compromises I made. I could not justify the high dollar oem MB fuel pumps and o2 sensors new, because if they did not fix the car, I'd be out the money and like a snowball rolling downhill in expenses for repairs on this one. I did put in NOS MB front foglights, and the correct caps/rotors, and a used MB coil, and used MB LH modules. I use the original parts where feasible. each part is a judgement call.
 

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'97 CL600
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2,845 Posts
Discussion Starter #14
1994, I rarely buy MB OEM replacements but look at Bosch and other German/European suppliers. My '97 CL600 has individual coils per cylinder. 12 at $140 each from MB or 12 at $55 each (same Bosch coil) from amazon.com. In reality all you need to do is input the MB part number into your browser and one gets a number of suppliers for the same part number.
Anziani
 

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Premium Member
1999 S600 & 1999 S500
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803 Posts
1994, I rarely buy MB OEM replacements but look at Bosch and other German/European suppliers. My '97 CL600 has individual coils per cylinder. 12 at $140 each from MB or 12 at $55 each (same Bosch coil) from amazon.com. In reality all you need to do is input the MB part number into your browser and one gets a number of suppliers for the same part number.
Anziani
I agree. I tried buying cheap headlight assemblies for my wife's 2005 4-Runner. They were all yellowed and wanted to "surprise" her for her birthday. They never fit right and actually had part of the beam missing. Light spread looked like a pacman! Went to the dealer and they gave us the parts half price and labor was maybe two hours. The cheap ones was the worst $150 dollar mistake of my life.

I got the same Bosch coils for my car. If I am doing my own labor I am going to use OEM or OEM equivalent Aftermarket parts from reputable providers.

Except,
I am almost finished with a drivers side mirror repair. I bought the cast (pot metal) frame from ebay provider in Chicago who I think gets them from Turkey for $20. I did have to drill another hole in it for one of the pins to go thru. It was advertised as OK for an E-class, but except for the missing hole has worked fine. I also bought the gaskets left and right from an ebay provider for $40 for the set. I had to use a scalpel to correct the holes and may seal the rest with liquid lectric tape or liquid gasket material. This was my only choice. I could buy a new mirror assembly from MB for $700/ of a used assy for $150to $200. From a cosmetic standpoint, these will look awesome, compare to the 20 year old gasket I had. I will change the gasket on the right side maybe next weekend. MAVA has an excellent write-up on this process.
 

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1994 s600 coupe
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364 Posts
anz, you are preaching to the choir, I bought like 6 sets of caps/rotors, just to decipher which ones were identical oem parts being sold in the aftermarket. I've been doing this a long, long time. 40 years. sourcing parts is an art and skill until itself, and many times used original in good condition is the best bang for buck, if you can find it. NOS old stock leftover from a closed store or dealer is also a great source, as is original owners who bought parts and never put them on the car, and just want them out of their house or garage.
 
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